Demystifying the Science and Art of Political Polling - By Mark Blumenthal

September 19, 2005

Katrina: New Data and Charts from SUSA

A quick note: SurveyUSA has continuesd to track reaction to the response to Hurricane Katrina in surveys conducted over the last week. The latest installment, released this morning, shows approval for President Bush's "response to Hurricane Katrina" at 40%, disapproval at 56%.

Unbeknownst to MP utnil this weekend, SurveyUSA also recently started posting complete time-series graphics for every question. Here is how you find the charts (links that follow are for the most recent Katrina poll): Each SurveyUSA "breaking news" poll report now includes a link at the bottom of the page for "complete interactive crosstabs." Click that to see demographic crosstabulations for each question. Clicking on the large white letter "T" on a black background in the upper left corner of each table will generate a time series graph that shows a time series chart for the question, like the one copied below (albeit in tiny form). Click on the pull-down menu at the upper left of the chart/table and you can modify the base of the chart, changing "all adults" to say, "gender: female" or "race: black." The "margin of error" at the top of each column changes automatically to take into account smaller subgroup sizes.

The analysis posted on the SurveyUSA site notes that Bush's approval is "down" two points since his speech on Thursday night, but to MP's eye the recent variation looks mostly like trendless random variation since about September 7. The 40% approval rating reported today is only one point different than the average of values SurveyUSA has reported since September 7 (41% approve, 55% disapprove). In fact, MP sees no difference in the average approval rating for the nine days before the speech (9/7-15) compared to the last three days after (9/16-18) - both show 41% approval, 55% disapproval. Either way, SurveyUSA now provides graphics like this for every question on every one of their breaking news polls, so you can reach your own conclusions. Just follow the links.

An interesting and more statistically significant trend highlighted in the written analysis appears on the question of whether the federal government is doing too much, not enough or just the right amount to help the victims of Hurricane Katrina. As this chart shows, the "not enough" percentage has fallen 10 percentage points (from 56% to 46%) since last Tuesday, while the number who say the government is doing "too much" has doubled (from 7% to 15%).

Say what you will about the sampling issues raised by SurveyUSA's automated interviewing methodology (and MP will have more to say soon), their new graphical charting and cross-tab software is quite unique. It's worth a few clicks to explore.

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